A recent study suggests that reducing calorie intake for just five days a month improves immunity and reduces several risk factors for cancer, diabetes and cognitive decline.
In all cultures of the world, fasting has always been seen as a means of purifying body and mind. For the ancient Greeks like Socrates, Plato and Pythagoras, fasting was considered essential to better perceive the truth, while for the followers of the Jewish, Christian, Muslim religions or even in Buddhism, fasting is used to get closer to God or to obey his commands.
Fasting still retains a certain esoteric dimension today, being seen as a way of “detoxifying” the body, a sort of purge that rids it of the “toxins” that have accumulated.
This vision of fasting is completely inaccurate: our body does not accumulate toxins and is on the contrary quite capable of eliminating harmful substances by itself thanks to the liver and our kidneys, without having to deprive ourselves of food to get there.
That said, several studies conducted over the past few years indicate that fasting still has dramatic effects on several aspects of metabolism.
For example, the simple act of restricting caloric intake over a period of eight hours followed by 16 hours without eating anything (intermittent fasting) is associated with a beneficial impact on blood glucose and insulin levels as well as a decrease in inflammation.
These positive effects on metabolism are even more pronounced for occasional longer fasts (2-3 days), which are also associated with regeneration of the immune system as well as protection against the toxic effects of chemotherapy in cancer patients.
Fasting is therefore not a method of detoxification, but rather a “reboot” of the metabolism which allows it to improve its performance and better resist attacks.
Fasting: spectacular results
Despite these positive effects, it is difficult to see occasional fasting as a realistic approach to improving population health. For the majority of people, it is psychologically very difficult, if not impossible, to completely deprive themselves of food for 2-3 days. Not to mention that the pure and simple elimination of all calorie intake can lead to serious complications in some people, especially in the elderly and frail.
It is in this context that a team of American researchers (University of South California) had the idea of developing a diet that reproduces the positive effects of fasting on the body, without however requiring the total abandonment of food. .
Essentially based on foods of plant origin, this diet cuts calorie intake by about half (800-1000 kcal per day), while providing adequate amounts of essential nutrients (vitamins, minerals, amino acids, Fatty acids).
The results obtained following the administration of this diet are quite spectacular: for example, adult mice subjected twice a month to four-day cycles of this low-calorie diet see their health greatly improved, with a reduction in abdominal fat, a reduction in the incidence of cancer, better bone density and increased life expectancy.
In older mice, this diet also leads to an increase in the synthesis of new neurons in the hippocampus and a significant improvement in their cognitive performance.
Fasting five days a month helps prevent chronic diseases
The results of a pilot study carried out with volunteers suggest that these benefits are also observed in humans. The participants (average age 40) were put on the fasting-mimicking diet five days a month for a period of three months, after which markers of their general health were measured and compared to those of a another group that had not been subjected to this calorie restriction.
The study clearly shows that the simple act of limiting calorie intake for a few days each month is enough to cause a significant decrease in blood sugar, inflammation and certain growth factors involved in tumor progression (IGF-1 ).
Since this caloric restriction was very well tolerated by the participants (only 5% drop-out), future clinical trials should make it possible to study in more detail its impacts on health and to confirm its potential for the prevention of chronic diseases and on life expectancy.
In the meantime, one thing is certain: most of the chronic diseases currently affecting the population are a consequence of overconsumption of food and there are only advantages to reducing the size of our portions.
Longo VD and MP Mattson. “Fasting: molecular mechanisms and clinical applications.” Cell Metab.; 19: 181-192. Brandhorst S et al. “A periodic diet that mimics fasting promotes multi-system regeneration, enhanced cognitive performance, and healthspan”. Cell Metab; 22:86-99.
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